Two-terminal resistive random access memories can be used as large-capacitance nonvolatile memories. Such types of memory are capable of low-voltage and low-current operations, high-speed switching, and micronization and high integration of memory cells. Various materials have been proposed as variable resistance layers for resistive random access memories.
In large-capacitance memory arrays, a plurality of metal wirings called bit lines and word lines are disposed to intersect each other and memory cells are formed at intersections of the bit lines and the word lines. A memory cell is written by applying a voltage to a bit line BL and a word line WL connected to the cell.